[David L.]

The practice in the places where I have worked differs to what stuartnz suggested, so I thought I'd better check up on this:
A common usage of per procurationem occurs in business letters, which are often signed on behalf of another person. For example, given a secretary authorized to sign a letter on behalf of the president of a company, the signature takes the form:
p.p. Secretary's Signature
President's Name
or
President's Name
p.p. Secretary's Signature
Commonly in practice, an alternative form is used:
Secretary's Signature
p.p. President's Name
The correct usage is the subject of some debate; largely depending on whether one interprets per procurationem as "through the agency of" or "on behalf of".
I know my secretary always put the p.p. before her name! The only answer to this one: see what the secretaries in your organization are doing!